As the high-speed Internet has been developed, users' requirements for various services using the Internet have been increased.
In this regard, users manage IDs and passwords for the respective services or respective application programs. Further, the application programs or companies such as a company providing a financial service requests personal information such as passwords for certificates in addition to the IDs and passwords for the IDs from the users in order to control access of the users.
However, since the variety and number of the services have been increasing, the number of the IDs and passwords for the IDs has also been increased correspondingly, which has caused the users' great inconvenience.
Specifically, since the variety and number of the services based on smart devices have been increasing, managing the respective IDs, passwords for each service has caused social expenses in addition to the users' inconvenience. In other words, users usually have same or different authentication information for each of services, and the service provider should manage the authentication information on the users for each of the services, which causes unnecessary expenses.
To solve this problem, an authentication system named Single Sign On (SSO) has been introduced to the various services and application programs recently, providing both the users and the companies with efficient management of the IDs and passwords.
However, the SSO has a shortcoming that hackers can access all services used by a specific user by stealing specific authentication information on the specific user only once.
Thus, there is a need for developing new algorithms to efficiently protect the authentication information on the users, such as personal information, from external attacks while also providing integrated login such as the SSO.